Jos Seegers - Academia.edu (original) (raw)
Papers by Jos Seegers
United European Gastroenterology Journal
Clinical Infectious Diseases
Background Patients with multiple recurrent Clostridioides difficile infections (rCDI) are treate... more Background Patients with multiple recurrent Clostridioides difficile infections (rCDI) are treated with fecal microbiota transplantation (FMT) provided by healthy donors. Blastocystis colonization of donors is considered an exclusion criterion, whereas its pathogenicity is still under debate. Methods The introduction of molecular screening for Blastocystis sp. at our stool bank identified two donors with prior negative microscopy but positive PCR. Potential transmission of Blastocystis sp. to patients was assessed on 16 fecal patient samples, pre- and post-FMT, by PCR and subtype (ST) analysis. In addition, clinical outcome for treatment of rCDI (n=31), as well as development of gastrointestinal symptoms was assessed. Results One donor carried Blastocystis ST1, the other contained ST3. All patients tested Blastocystis negative prior to FMT. With a median of 20.5 days after FMT, 8 of 16 (50%) patients developed intestinal colonization with Blastocystis, with identical ST-sequences as...
Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases, Jan 18, 2017
Since 2013, several stool banks have been developed following publications reporting on clinical ... more Since 2013, several stool banks have been developed following publications reporting on clinical success of "Fecal Microbiota Transplantation" (FMT) for recurrent Clostridium difficile infections (CDI). However, protocols for donor screening, fecal suspension preparation and transfer of the fecal suspension differ between various countries and institutions. Moreover, no European consensus exists regarding the legislative aspects of the fecal suspension product. Internationally standardized recommendations about the above mentioned aspects have not yet been established. In 2015, the Netherlands Donor Feces Bank (NDFB) was founded with the primary aim to provide a standardized product for the treatment of patients with recurrent CDI in the Netherlands. Standard operation procedures for donor recruitment, donor selection, donor screening, and production, storage and distribution of frozen fecal suspensions for FMT were formulated. Our experience summarized in this review addr...
Vaccine, 2016
Yersinia pestis, one of history's deadliest pathogens, has killed... more Yersinia pestis, one of history's deadliest pathogens, has killed millions over the course of human history. It has attributes that make it an ideal choice to produce mass casualties and is a prime candidate for use as a biological weapon. When aerosolized, Y. pestis causes pneumonic plague, a pneumonia that is 100% lethal if not promptly treated with effective antibiotics. Currently, there is no FDA approved plague vaccine. The current lead vaccine candidate, a parenterally administered protein subunit vaccine comprised of the Y. pestis virulence factors, F1 and LcrV, demonstrated variable levels of protection in primate pneumonic plague models. As the most likely mode of exposure in biological attack with Y. pestis is by aerosol, this raises a question of whether this parenteral vaccine will adequately protect humans against pneumonic plague. In the present study we evaluated two distinct mucosal delivery platforms for the intranasal (IN) administration of LcrV and F1 vaccine proteins, a live bacterial vector, Lactobacillus plantarum, and a Tobacco Mosaic Virus (TMV) based delivery platform. IN administration of L. plantarum expressing LcrV, or TMV-conjugated to LcrV and F1 (TMV-LcrV+TMV-F1) resulted in the similar induction of high titers of IgG antibodies and evidence of proinflammatory cytokine secretion. However, only the TMV-conjugate delivery platform protected against subsequent lethal challenge with Y. pestis. TMV-LcrV+TMV-F1 co-vaccinated mice had no discernable morbidity and no mortality, while mice vaccinated with L. plantarum expressing LcrV or rLcrV+rF1 without TMV succumbed to infection or were only partially protected. Thus, TMV is a suitable mucosal delivery platform for an F1-LcrV subunit vaccine that induces complete protection against pneumonic infection with a lethal dose of Y. pestis in mice.
Biology of Growing Animals, 2005
Applied and environmental microbiology, 1997
The bacteriocins lactococcin B and pediocin PA-1 were purified by ethanol precipitation, preparat... more The bacteriocins lactococcin B and pediocin PA-1 were purified by ethanol precipitation, preparative isoelectric focusing, and ultrafiltration. The procedure reproducibly leads to high final yields in comparison to the generally low yields obtained by column chromatography. Specifically, during isoelectric focusing no loss of activity occurs. The method, in general, should be applicable to small, hydrophobic, cationic bacteriocins.
Applied and environmental microbiology, 1993
The effects of the rolling-circle and theta modes of replication on the maintenance of recombinan... more The effects of the rolling-circle and theta modes of replication on the maintenance of recombinant plasmids in Lactococcus lactis were studied. Heterologous Escherichia coli or bacteriophage lambda DNA fragments of various sizes were inserted into vectors based on either the rolling-circle-type plasmid pWV01 or the theta-type plasmid pAMbeta1. All pAMbeta1 derivatives were stably maintained. pWV01 derivatives, however, showed size-dependent segregational instability, in particular when large DNA fragments were inserted. All recombinant pWV01 derivatives generated high-molecular-weight plasmid multimers (HMW) in amounts that were positively correlated with plasmid size and inversely correlated with the copy numbers of the monomeric plasmid forms. Formation of HMW or reductions in copy numbers were not observed with pAMbeta1 derivatives. The results indicate that HMW formation and/or reduction in plasmid copy numbers is an important factor in the maintenance of pWV01 derivatives. It i...
Current opinion in molecular therapeutics, 2000
By expression of foreign antigens in attenuated strains derived from bacterial pathogens and in n... more By expression of foreign antigens in attenuated strains derived from bacterial pathogens and in non-pathogenic commensal bacteria, recombinant vaccines are being developed that aim to stimulate mucosal immunity. Recent advances in the pathogenesis and molecular biology of these bacteria have allowed rational development of new and improved bacterial carriers and more effective gene expression systems. These advances have improved the performance and versatility of these delivery systems to induce mucosal immunity to recombinant antigens in animal models. Application of these (improved) technologies for development of human vaccines is still limited and awaits further exploration.
Applied and environmental microbiology, 1999
A specific fragment of the genome of Tuc2009, a temperate lactococcal bacteriophage, was shown to... more A specific fragment of the genome of Tuc2009, a temperate lactococcal bacteriophage, was shown to contain several open reading frames, whose deduced protein products exhibited similarities to proteins known to be involved in DNA replication and modification. In this way, a putative single-stranded binding protein, replisome organizer protein, topoisomerase I, and a methylase were identified. When the genetic information coding for the putative replisome organizer protein of Tuc2009, Rep2009, was supplied on a high-copy-number plasmid vector, it was shown to confer a phage-encoded resistance (Per) phenotype on its lactococcal host UC509.9. The presence of this recombinant plasmid was shown to cause a marked reduction in Tuc2009 DNA replication, suggesting that the observed phage resistance was due to titration of a factor, or factors, required for Tuc2009 DNA replication. Further experiments delineated the phage resistance-conferring region to a 160-bp fragment rich in direct repeats...
Microbial Growth in Biofilms, Pt a R Biological Aspects, 2001
... Letr 169, 29 (1998). 9 DM Shaw, RJ Leer, C. Smittenaar, M.-J. Heijne den Bak-Glashouwer, FJ T... more ... Letr 169, 29 (1998). 9 DM Shaw, RJ Leer, C. Smittenaar, M.-J. Heijne den Bak-Glashouwer, FJ Tielen, and PH Pouwels, Immunology 100, 510 (2000). ... The shortened sequence comprises the AT-rich 5 ~ region but lacks the signal sequence peptidase site. ...
Trends in Biotechnology, 2002
Evidence is accumulating that lactobacilli influence the immune response in a strain-dependent ma... more Evidence is accumulating that lactobacilli influence the immune response in a strain-dependent manner. This immunomodulatory capacity is important for the development of the immune response, and also identifies Lactobacillus as a potent oral vaccine carrier. Most of our current knowledge of the use of lactobacilli for vaccination purposes has been obtained with tetanus toxin fragment C (TTFC) as the model antigen. This knowledge, together with our ever-increasing understanding of the immune system and recent developments in cloning and expression techniques, should enable the utilisation of antigens other than TTFC and has made the development of lactobacilli as live vaccines a realistic prospect.
Proceedings of the National Academy of Sciences, 2003
United European Gastroenterology Journal
Clinical Infectious Diseases
Background Patients with multiple recurrent Clostridioides difficile infections (rCDI) are treate... more Background Patients with multiple recurrent Clostridioides difficile infections (rCDI) are treated with fecal microbiota transplantation (FMT) provided by healthy donors. Blastocystis colonization of donors is considered an exclusion criterion, whereas its pathogenicity is still under debate. Methods The introduction of molecular screening for Blastocystis sp. at our stool bank identified two donors with prior negative microscopy but positive PCR. Potential transmission of Blastocystis sp. to patients was assessed on 16 fecal patient samples, pre- and post-FMT, by PCR and subtype (ST) analysis. In addition, clinical outcome for treatment of rCDI (n=31), as well as development of gastrointestinal symptoms was assessed. Results One donor carried Blastocystis ST1, the other contained ST3. All patients tested Blastocystis negative prior to FMT. With a median of 20.5 days after FMT, 8 of 16 (50%) patients developed intestinal colonization with Blastocystis, with identical ST-sequences as...
Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases, Jan 18, 2017
Since 2013, several stool banks have been developed following publications reporting on clinical ... more Since 2013, several stool banks have been developed following publications reporting on clinical success of "Fecal Microbiota Transplantation" (FMT) for recurrent Clostridium difficile infections (CDI). However, protocols for donor screening, fecal suspension preparation and transfer of the fecal suspension differ between various countries and institutions. Moreover, no European consensus exists regarding the legislative aspects of the fecal suspension product. Internationally standardized recommendations about the above mentioned aspects have not yet been established. In 2015, the Netherlands Donor Feces Bank (NDFB) was founded with the primary aim to provide a standardized product for the treatment of patients with recurrent CDI in the Netherlands. Standard operation procedures for donor recruitment, donor selection, donor screening, and production, storage and distribution of frozen fecal suspensions for FMT were formulated. Our experience summarized in this review addr...
Vaccine, 2016
Yersinia pestis, one of history's deadliest pathogens, has killed... more Yersinia pestis, one of history's deadliest pathogens, has killed millions over the course of human history. It has attributes that make it an ideal choice to produce mass casualties and is a prime candidate for use as a biological weapon. When aerosolized, Y. pestis causes pneumonic plague, a pneumonia that is 100% lethal if not promptly treated with effective antibiotics. Currently, there is no FDA approved plague vaccine. The current lead vaccine candidate, a parenterally administered protein subunit vaccine comprised of the Y. pestis virulence factors, F1 and LcrV, demonstrated variable levels of protection in primate pneumonic plague models. As the most likely mode of exposure in biological attack with Y. pestis is by aerosol, this raises a question of whether this parenteral vaccine will adequately protect humans against pneumonic plague. In the present study we evaluated two distinct mucosal delivery platforms for the intranasal (IN) administration of LcrV and F1 vaccine proteins, a live bacterial vector, Lactobacillus plantarum, and a Tobacco Mosaic Virus (TMV) based delivery platform. IN administration of L. plantarum expressing LcrV, or TMV-conjugated to LcrV and F1 (TMV-LcrV+TMV-F1) resulted in the similar induction of high titers of IgG antibodies and evidence of proinflammatory cytokine secretion. However, only the TMV-conjugate delivery platform protected against subsequent lethal challenge with Y. pestis. TMV-LcrV+TMV-F1 co-vaccinated mice had no discernable morbidity and no mortality, while mice vaccinated with L. plantarum expressing LcrV or rLcrV+rF1 without TMV succumbed to infection or were only partially protected. Thus, TMV is a suitable mucosal delivery platform for an F1-LcrV subunit vaccine that induces complete protection against pneumonic infection with a lethal dose of Y. pestis in mice.
Biology of Growing Animals, 2005
Applied and environmental microbiology, 1997
The bacteriocins lactococcin B and pediocin PA-1 were purified by ethanol precipitation, preparat... more The bacteriocins lactococcin B and pediocin PA-1 were purified by ethanol precipitation, preparative isoelectric focusing, and ultrafiltration. The procedure reproducibly leads to high final yields in comparison to the generally low yields obtained by column chromatography. Specifically, during isoelectric focusing no loss of activity occurs. The method, in general, should be applicable to small, hydrophobic, cationic bacteriocins.
Applied and environmental microbiology, 1993
The effects of the rolling-circle and theta modes of replication on the maintenance of recombinan... more The effects of the rolling-circle and theta modes of replication on the maintenance of recombinant plasmids in Lactococcus lactis were studied. Heterologous Escherichia coli or bacteriophage lambda DNA fragments of various sizes were inserted into vectors based on either the rolling-circle-type plasmid pWV01 or the theta-type plasmid pAMbeta1. All pAMbeta1 derivatives were stably maintained. pWV01 derivatives, however, showed size-dependent segregational instability, in particular when large DNA fragments were inserted. All recombinant pWV01 derivatives generated high-molecular-weight plasmid multimers (HMW) in amounts that were positively correlated with plasmid size and inversely correlated with the copy numbers of the monomeric plasmid forms. Formation of HMW or reductions in copy numbers were not observed with pAMbeta1 derivatives. The results indicate that HMW formation and/or reduction in plasmid copy numbers is an important factor in the maintenance of pWV01 derivatives. It i...
Current opinion in molecular therapeutics, 2000
By expression of foreign antigens in attenuated strains derived from bacterial pathogens and in n... more By expression of foreign antigens in attenuated strains derived from bacterial pathogens and in non-pathogenic commensal bacteria, recombinant vaccines are being developed that aim to stimulate mucosal immunity. Recent advances in the pathogenesis and molecular biology of these bacteria have allowed rational development of new and improved bacterial carriers and more effective gene expression systems. These advances have improved the performance and versatility of these delivery systems to induce mucosal immunity to recombinant antigens in animal models. Application of these (improved) technologies for development of human vaccines is still limited and awaits further exploration.
Applied and environmental microbiology, 1999
A specific fragment of the genome of Tuc2009, a temperate lactococcal bacteriophage, was shown to... more A specific fragment of the genome of Tuc2009, a temperate lactococcal bacteriophage, was shown to contain several open reading frames, whose deduced protein products exhibited similarities to proteins known to be involved in DNA replication and modification. In this way, a putative single-stranded binding protein, replisome organizer protein, topoisomerase I, and a methylase were identified. When the genetic information coding for the putative replisome organizer protein of Tuc2009, Rep2009, was supplied on a high-copy-number plasmid vector, it was shown to confer a phage-encoded resistance (Per) phenotype on its lactococcal host UC509.9. The presence of this recombinant plasmid was shown to cause a marked reduction in Tuc2009 DNA replication, suggesting that the observed phage resistance was due to titration of a factor, or factors, required for Tuc2009 DNA replication. Further experiments delineated the phage resistance-conferring region to a 160-bp fragment rich in direct repeats...
Microbial Growth in Biofilms, Pt a R Biological Aspects, 2001
... Letr 169, 29 (1998). 9 DM Shaw, RJ Leer, C. Smittenaar, M.-J. Heijne den Bak-Glashouwer, FJ T... more ... Letr 169, 29 (1998). 9 DM Shaw, RJ Leer, C. Smittenaar, M.-J. Heijne den Bak-Glashouwer, FJ Tielen, and PH Pouwels, Immunology 100, 510 (2000). ... The shortened sequence comprises the AT-rich 5 ~ region but lacks the signal sequence peptidase site. ...
Trends in Biotechnology, 2002
Evidence is accumulating that lactobacilli influence the immune response in a strain-dependent ma... more Evidence is accumulating that lactobacilli influence the immune response in a strain-dependent manner. This immunomodulatory capacity is important for the development of the immune response, and also identifies Lactobacillus as a potent oral vaccine carrier. Most of our current knowledge of the use of lactobacilli for vaccination purposes has been obtained with tetanus toxin fragment C (TTFC) as the model antigen. This knowledge, together with our ever-increasing understanding of the immune system and recent developments in cloning and expression techniques, should enable the utilisation of antigens other than TTFC and has made the development of lactobacilli as live vaccines a realistic prospect.
Proceedings of the National Academy of Sciences, 2003